NIDA defines its role in terms of reducing the harm caused by drug abuse. In order to achieve this goal, it is necessary to understand the mechanisms that contribute to reductions in the consumption of these substances, both behavioral and biological, and at both the individual and population levels. Unfortunately, very little is known today about the simultaneous consumption at the population level of multiple psychoactive substances, such as cannabinoids and opiates; one or both sets of substances are illegal in the U.S.A. and the rest of the world, making reliable consumption and related data at the population level impossible to collect and analyze. In this context, the broad goal of this project is to explore and fill this gap. Specifically, the aim of this project is to significantly advance our knowledge of the behavior of multiple drug-consuming populations with a series of analyses using a unique recently-discovered and extraordinarily rich and reliable dataset on the consumption of multiple addictive substances collected at a time when the consumption of these substances was legal. The dataset will contain annual population-level statistics for over fifty districts from British India over a three-decade period in the early 20th century on the consumption and prices of alcohol (in multiple forms/strengths), opium, and cannabis (in multiple forms, namely charas (hashish), ganja, and bhang (straight leaf)). Corresponding information on wages, the cost of living, taxation and a variety of other pertinent economic and non-economic information will also be collected and entered. This unique dataset will enable the pursuit of at least six specific aims, including analyses of (i) the addictiveness (using economic models of addiction) of each of these substances in a multi-substance setting using legal data, (ii) substitution and complementarity of all of these substances (including their various forms, as in marijuana and alcohol, and their various strengths, as in alcohol) with one another, (iii) the price sensitivity at the population level of marijuana, alcohol, and opium consumption in the presence of different forms and strengths of the same and other substances, (iv) the analysis of differential behavior depending on the strength of some of these substances (such as alcohol based on alcohol content and cannabinoids based on form, each of which has a different potency (i.e., charas vs. ganja vs. bhang)), (v) whether the consumption of one or more substances or forms of substances tends to systematically precede in time the consumption of one or more of the other substances or forms of substances, and (vi) the interrelationships of the multiple substances in their various strengths and forms ((ii) and (v) above) as a system with characteristics informed by graph theory. The body of knowledge generated by these analyses will significantly advance drug research by informing strategies for reducing the harm caused by drug consumption. [unreadable] [unreadable] [unreadable] [unreadable]